Why limit of font-size for Inline-SVG? Bug?

I generate bar-diagramms with random numbers on the page http://www.düddelei.de/en/2018/test-of-svt/. The diagramm are definind in svg.
The bar-diagrams contain text. The font-size of the text is calculated from the random numbers. The font-size is sometime greater than 10000px. The text is then not readable.